旋转机械动静碰摩机理研究

Mechanism Study of Rotor to Stator Rub Characteristics for Rotating Machinery

通过引入混沌理论对碰摩的非线性特征进行了理论分析及数值求解 ,研究不平衡力和转速等条件发生变化时 ,碰摩的发展历程。结果表明 ,随控制参数转速的变化 ,碰摩出现从稳定周期运动经过倍周期分叉到达混沌的特征。文中对某电厂 2 0 0 MW机组出现的碰摩故障进行了实际分析和理论对照 。

For steam turbine in the plant, in order to improve the efficiency, th e gap between rotor and stator is usually designed to be very small. Numerous di sturba nces, such as unbalance forces and gap change, will lead to impact between stato r and rotor. The subsection motive equation of rubbing impact rotor model is bu i lt to explore the chaotic characteristics of rub vibration. Numerical integral r esults indicate that different forms of rub impact are taken on with the change of unbalance force and speed ratio. When speed ratio increases from 0 to 20, rub impact motion will go through an extraordinary route to chaos by multi cycle bi furcation. Moreover, multi cycle bifurcation and chaos phenomenon appear altern a tely in the whole process. Meanwhile rotor to stator rub takes on abundant frequ ency characteristics. Rubbing impact vibration of turbine shaft is also analyze d in detail based on the samples collected in the power plant. Similar character istics of f requency spectrum during development of chaos to that of numerical analysis can be obtained. The theoretic contribution to diagnose the rotor to stator rub fault in rotating machinery is concluded.